Texas scientists surveyed commercial and residential citrus trees from 2007 to 2017, closely monitoring the proportion of citrus trees and the Asian citrus psyllid (ACP). The results were published by the American Phytopathological Society; study co-author Dr. Olufemi Alabi is an expert in Plant Pathology and Microbiology at Texas A&M University.
“Unlike previous studies on citrus greening disease epidemics that were typically initiated in commercial orchards after the disease had been introduced or became widespread in the area, our study commenced 5-years prior to the first detection of the greening bacterium in Texas and continued for 5 additional years,” explained Dr. Alabi. “This gave us the unique opportunity to obtain a holistic picture of the progression of the disease epidemics from its onset in both commercial and residential ecologies.”
Even though citrus greening first appeared in Florida in 2005, the infectious bacteria was not found in Texas until 2011, when scientists detected it in psyllids. Citrus trees remained disease-free in Texas until 2012, which indicates that psyllids could be used for early detection of the HLB pathogen as it invades new areas.
During the decade-long study, the proportion of infected trees and psyllids increased exponentially over time, according to the researchers. By 2017, at least one citrus tree was infected in 26 percent of fields and in 40 percent of residential backyards.
The experts also identified seasonal fluctuations that will provide new insight into the ongoing citrus greening epidemic in Texas. The findings may also help to inform other regions that have not yet been affected by citrus greening.